This invention pertains to a catalytic composition for use in hydrocracking processes to maximize middle distillate yield from hydrocarbons boiling above about 650.degree. F., which composition comprises an alumina-zeolite support, a rare earth exchange metal component, at least one metal component selected from Group VIB or Group VIII and from about 0.9 to about 5 wt. % of at least one component selected from Group IA based on the weight of the finished catalyst. A considerable number of materials have been heretofore proposed as catalysts for hydrocracking hydrocarbon oils. In the past few years much attention has been devoted to using crystalline aluminosilicates as a component in such hydrocracking catalysts. In general, the crystalline aluminosilicates are used in combination with a porous matrix such as silica-alumina. In some cases the co-catalytic activity of the crystalline aluminosilicate material and the acidic porous matrix with various metallic promoters has been found to be an effective catalyst material.